July 9, 2009 -- Health officials are looking toward thousands of schools and day care centers to mount a possible mass vaccination program against the H1N1 swine flu this fall, government planners said Thursday.

The Latest on H1N1 Swine Flu

The plan -- which still depends on unanswered questions of how easy a swine flu vaccine is to produce and how well it works -- could see tens of millions of doses targeted mainly at children beginning in October, Obama administration officials said.

Swine flu has sickened an estimated 1 million Americans since it was first identified in the U.S. in the spring. Approximately 170 U.S. deaths have been reported.

The widely publicized outbreak was thought to have originated in Mexico. It sent health officials and manufacturers scrambling to produce a vaccine against H1N1 swine flu. Test lots of vaccine are soon to enter clinical trials to see how well the vaccine works in helping the body mount immune protection against the H1N1 swine flu virus and how many doses it might take to get that protection.

New infections continue across the U.S. this summer. Experts expect the virus to infect many more people in the fall, when flu viruses typically spread much more easily and outbreaks can take hold.

"Since the population that seems to be most affected is younger folks, school-aged kids, kids in day care centers, we may well partner with the schools, looking at those as possible sights for a vaccination program," said Kathleen Sebelius, the secretary of the Department of Health and Human Services.

At a meeting Thursday at the National Institutes of Health headquarters in Bethesda, Md., Sebelius urged state and local officials to "be prepared for the potential of a fall vaccination campaign."

Officials said they were planning on a voluntary vaccination program focusing on children, adults with underlying diseases, health care workers, and families of small children and infants.

"What we can't do is wait until October and then suddenly decide that we have very serious situation on our hands," Sebelius said.

Production of Swine Flu Vaccine

Five U.S. vaccine makers are ramping up production of an H1N1 swine flu vaccine. The vaccine is entering trials to test its effectiveness, and also to determine if it will have to be delivered in more than one dose.

Results of the trials are expected in August, said Anthony Fauci, MD, head of the National Institute of Allergy and Infectious Diseases. After that, companies are likely to start producing a vaccine with a plan to distribute doses by October.

"We're probably talking about tens of millions of doses in early October," Fauci said.

Bruce Gellin, MD, head of the National Vaccine Program at the Department of Health and Human Services, said companies could produce as much as 100 million doses of H1N1 swine flu vaccine. "This is, if all goes well," he said.

At the same time, epidemiologists are closely monitoring the Southern hemisphere, where flu season is in full swing. Flu viruses mutate easily, and scientists are watching to see if the current H1N1 virus undergoes genetic changes that make it easier to spread, more resistant to vaccine protection, or more lethal.

Officials are also trying to coordinate with state and local officials. They need to set up protocols for vaccine distribution, anti-viral drug distribution, and guidelines for closing schools where infected students are found.

Hundreds of schools across the nation closed for days or weeks at a time during the spring after students became infected with swine flu. In New York City, where the outbreak was particularly strong, 55 schools closed, 900 people were hospitalized, and more than 45 people died.

Officials still have not decided exactly which age groups will be recommended to get the vaccine. That decision is likely to come at the end of July when the federal Advisory Council on Immunization Practices meets in Atlanta.

Anne Schuchat, MD, who heads the National Center for Immunization and Respiratory Diseases at the CDC, told state and local officials to expect "a very busy fall."

"This is a time for aggressive planning, and I hope you recognize that we have a lot to plan for," she said.